Well the one thing you didn't mention was how much you are willing to spend. And with out all the specs of the engine it is hard to tell.
You could always go with a bigger stoke. 4.500" will give you 598ci and a 4.750" will give you 632ci. And we all know that more CI will get you what you want, more power and torque.

just my 2¢ worth


gyrogearloose

I've thought about putting the 4.5" stroke in there and even talked to my engine guy a little about it. For the cost crank, balance job that is not the most cost affective way to gain very little. Hopefully we come up with something thinking the heads need a hand port to them.

Go with BIG DUKES that'll add your 50 and a whole lot more :) :wink:

I wish I could wing that right now but just not in the pocket book to do so. I drive a buddies car once in awhile its a big duke motor 565, I was .05 faster then him last time we were out same weight cars :lol: